I think that part of the issue is the suburban sprawl. As many know, I started my railroad career with newly formed BNSF in Aurora. I left that job almost 20 years ago for one back east. Every few years I go back to visit friends. It also helps that my wife is a buff, and she likes to go out there. Each time more and more has built up. This now extends past the traditional boundary of Chicagoland, which had been Joliet, Aurora, and Elgin. A few years ago we had a thread about expanding BNSF service to Sandwich.
I think that these parking lot stations come in two varieties. First there are places like Route 59. That pulls in riders likely from places like Plainfield, Winfield, and Bolingbrook, and even southern Naperville, which aren't on any of the commuter lines. Sure, these customers could be well served by comprehensive bus service to the station. The second group are the rat race escapees. With the Chicagoland housing prices, choked roads. I think many of these people drive into stations near the end of the line. These people don't want to move to housing right near the station. I can see that the point about Tinley. I'll bet many come there from places south of the suburban area. Just like the western suburbs and beyond, bus service is slim to none.
In the Sandwich extension thread, the point was made that many who live out there work locally, or go to the industrial and office complexes around Aurora and Naperville. There's go to be a percentage who are willing to live the country life, yet commute to Chicago every day. Has a poll been taken at these parking lot stations, which asks where the customers live? It would be neat to see how far some come from. I'll bet that even DeKalb has some Chicago commuters.